reach_listContactsV1

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden. It discloses that the endpoint is paginated, returns basic contact information, supports filtering by group UUID and subscription status, and has the important limitation of falling back to the default profile. However, it does not detail page size, response shape, or authentication expectations, leaving some transparency gaps.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is compact and well-structured: one sentence for the core purpose, one for pagination, and one paragraph for deprecation with an alternative. Every sentence adds value, and the deprecation notice is clearly separated.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool has no output schema and no annotations, but the description covers the core usage, filters, pagination, and deprecation status. It does not describe the exact response structure (e.g., contact fields returned), which would be useful absent an output schema, but it effectively guides an agent to prefer the alternative endpoint. Overall, it is adequately complete for a deprecated, simple list operation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

All three parameters are described in the schema with 100% coverage. The description only repeats that filtering by group UUID and subscription status is possible, adding no extra semantics beyond the schema. The page parameter is not elaborated beyond 'Page number' in either place, so the description does not compensate beyond the baseline.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states 'Get a list of contacts, optionally filtered by group and subscription status,' specifying the resource (contacts) and the action (get list). It also notes pagination and marks the endpoint as deprecated, which differentiates it from sibling tools like reach_listProfileContactsV1 and reach_listSegmentContactsV1.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly states the tool is deprecated, cannot target a specific profile, and always falls back to the client's default profile. It provides a direct alternative ('Use `GET /api/reach/v1/profiles/{profileUuid}/contacts` instead') and explains the improvement, giving clear when-not-to-use and when-to-use guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.